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Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane
Cellular membranes have a complex phospholipid composition that varies greatly depending on the organism, cell type and function. In spite of this complexity, most structural data available for phospholipid bilayers concern model systems containing only one or two different phospholipids. Here, we e...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4704005/ https://www.ncbi.nlm.nih.gov/pubmed/26529029 http://dx.doi.org/10.3390/membranes5040664 |
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author | Cathcart, Kelly Patel, Amit Dies, Hannah Rheinstädter, Maikel C. Fradin, Cécile |
author_facet | Cathcart, Kelly Patel, Amit Dies, Hannah Rheinstädter, Maikel C. Fradin, Cécile |
author_sort | Cathcart, Kelly |
collection | PubMed |
description | Cellular membranes have a complex phospholipid composition that varies greatly depending on the organism, cell type and function. In spite of this complexity, most structural data available for phospholipid bilayers concern model systems containing only one or two different phospholipids. Here, we examine the effect of cholesterol on the structure of a complex membrane reflecting the lipid composition of mitochondrial membranes, with five different types of headgroups (phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS) and cardiolipin (CL)) and a variety of hydrocarbon tails. This particular system was chosen because elevated cholesterol contents in mitochondrial membranes have been linked to a breaking down of Bax-mediated membrane permeabilization and resistance to cancer treatments. High resolution electron density profiles were determined by X-ray reflectivity, while the area per phospholipid chain, [Formula: see text] , and the chain order parameter, [Formula: see text] , were determined by wide-angle X-ray scattering (WAXS). We show that chain order increases upon the addition of cholesterol, resulting in both a thickening of the lipid bilayer and a reduction in the average surface area per phospholipid chain. This effect, well known as cholesterol’s condensation effect, is similar, but not as pronounced as for single-component phospholipid membranes. We conclude by discussing the relevance of these findings for the insertion of the pro-apoptotic protein Bax in mitochondrial membranes with elevated cholesterol content. |
format | Online Article Text |
id | pubmed-4704005 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-47040052016-01-21 Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane Cathcart, Kelly Patel, Amit Dies, Hannah Rheinstädter, Maikel C. Fradin, Cécile Membranes (Basel) Article Cellular membranes have a complex phospholipid composition that varies greatly depending on the organism, cell type and function. In spite of this complexity, most structural data available for phospholipid bilayers concern model systems containing only one or two different phospholipids. Here, we examine the effect of cholesterol on the structure of a complex membrane reflecting the lipid composition of mitochondrial membranes, with five different types of headgroups (phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS) and cardiolipin (CL)) and a variety of hydrocarbon tails. This particular system was chosen because elevated cholesterol contents in mitochondrial membranes have been linked to a breaking down of Bax-mediated membrane permeabilization and resistance to cancer treatments. High resolution electron density profiles were determined by X-ray reflectivity, while the area per phospholipid chain, [Formula: see text] , and the chain order parameter, [Formula: see text] , were determined by wide-angle X-ray scattering (WAXS). We show that chain order increases upon the addition of cholesterol, resulting in both a thickening of the lipid bilayer and a reduction in the average surface area per phospholipid chain. This effect, well known as cholesterol’s condensation effect, is similar, but not as pronounced as for single-component phospholipid membranes. We conclude by discussing the relevance of these findings for the insertion of the pro-apoptotic protein Bax in mitochondrial membranes with elevated cholesterol content. MDPI 2015-10-30 /pmc/articles/PMC4704005/ /pubmed/26529029 http://dx.doi.org/10.3390/membranes5040664 Text en © 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Cathcart, Kelly Patel, Amit Dies, Hannah Rheinstädter, Maikel C. Fradin, Cécile Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane |
title | Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane |
title_full | Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane |
title_fullStr | Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane |
title_full_unstemmed | Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane |
title_short | Effect of Cholesterol on the Structure of a Five-Component Mitochondria-Like Phospholipid Membrane |
title_sort | effect of cholesterol on the structure of a five-component mitochondria-like phospholipid membrane |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4704005/ https://www.ncbi.nlm.nih.gov/pubmed/26529029 http://dx.doi.org/10.3390/membranes5040664 |
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